How I DECIMATED my aquaponics system and I have no idea why!

[Jeff]

One thing I wanted to bring up on this topic. Every year around this time, my tomato plants develop a white mold on the stem. Do you think this white mold could be causing any issues with the fish (poisoning them)?

[attachment=0:t0snr2gy]mold.JPG[/attachment:t0snr2gy]

The plant is still producing fruit, so that's the only reason why I haven't pulled it out.......but I am curious to know your opinions on it.

[JCO]

Powdery mildew on tomatoes attacks a plant’s foliage and stems.

First off, it will not harm your fish......

It’s more common in commercial tomato fields and greenhouses than in the home garden. But regardless of where it attacks, the fungus weakens plants and reduces productivity wherever it thrives.

Three types of powdery mildew fungus plague tomatoes: Oidium neolycopersici, Erysiphe orontii, andLeveillula taurica. Fungi are spread by airborne spores, transported by wind or pests, which land on leaves and germinate.

Powdery mildew needs living plant tissue in order to grow, but the fungi do not directly “kill” the tomato plants. Rather, they feed on the tomato plant’s cells. Yellowed (then brown) leaves remain, accompanied by white powdery growth. This “powdery mildew” (from which the disease gets its name) grows as thin layers on tomato leaf surfaces.

Three factors make tomato plants succumb to powdery mildew: environment (humidity or wet leaves), onset date (the earlier in the season, the more difficult controlling mildew), and treatment (the sooner, the better).

How to treat before symptoms appear.

One of the most effective preventative treatments is sulfur dusts and sprays . But be sure to apply the sulfur product on a still day, when temperatures are well below 90º F. Apply in morning or evening, because sulfur can burn tomato plants in the direct sunlight. If you’ve applied oils to tomato plants, wait at least two weeks before using a sulfur product.

You can also treat tomato plants preventatively with a biofungicide, made up of specially-formulated microorganisms that destroy fungi, it can help prevent mildew from infecting tomato plants. Follow label instructions.

How to treat affected plants.

Begin applications at the first sign of mildew. Horticultural oils or neem oil have helped reduce and sometimes eradicate powdery mildew on plants. Do not apply oils during a drought, when temperatures are above 90º F, or within two weeks of treating plants with a sulfur product.

In all cases, thoroughly cover plant with treatments. Repeat every 7-10 days or after rain.
Once mildew is present and progresses, it becomes more resistant to biofungicide and fungicide. Tomato Dirt best advice: treat preventatively or, if powdery mildew appears, treat as consistently as possible.

[Jeff]

Thanks JCO. It's good to know that it's harmless for the fish. I have never used any kind of fungal spray because I've always been paranoid that it would harm the fish. Have you ever experienced this kind of mildew before in your system?

[JCO]

Nope, I'm happy to say I have never had that malady in my grow bed...knock on wood

[Jeff]

Ok, another unfortunate update. Just when I thought that I may have it under control, ANOTHER fish has died.

He looked otherwise healthy from afar, but upon closer examination, it looks like some of his scales were missing. I took a picture for you to look at.....doesn't it look like their missing and not simply off colored. Note that the nitrite reading looks a little purple on camera, but it really is more towards the shade of light blue:

[attachment=2:3c34woqv]FishDeadMissingScales.JPG[/attachment:3c34woqv]

The only other thing I noticed was a possible red mark on a single fin, but I don't know if that was caused after death (as opposed to being a symptom of it):

[attachment=1:3c34woqv]RedFin.JPG[/attachment:3c34woqv]

All of my water looks good to me. Here's a pic of the exact readings this morning as soon as I took the dead fish out of there:

[attachment=0:3c34woqv]Readings.JPG[/attachment:3c34woqv]

I even have the water temp heated to about 76 degrees because I read that could help. (No, I didn't heat it up too fast.)

Water changes have been frequent. Almost every day, I either ADD 10 gallons of treated/salted water.......or every other day I will empty 10 gallons from the tank, and refill with 20 gallons. That second method is sort of my "gradual water change" approach, by removing a little but adding twice the amount back.

The only thing I can think of at this point is some kind of parasite or bacteria, since my chemical readings don't look to be out of whack. My question is this:

CAN I TREAT THE ENTIRE TANK WITH SOMETHING LIKE MARACIDE OR COPPERSAFE? Normally, we would frown on putting anything into the tank which supplies water to our veggies.....but since the weather is getting colder, I'm not really eating anything from the system anyway. I mainly leave the plants there for nitrate filtration.

I'm just wondering if any of you have ever treated your entire tank with medication before, and if so, have you any thoughts on either of those two as a global application to the entire system? I don't want to harm any "healthy" fish (I only have 7 left), but at this point, even the ones who look healthy may be fighting a losing battle to my untrained eye.

[David - WI]

Your pH looks like it's off-the-scale, so you need to use the "high range" pH test.

[Jeff]

Your pH looks like it's off-the-scale, so you need to use the "high range" pH test.

That's what I thought too, but it's not though. Here is the reading from this morning of the HIGH RANGE pH:

[attachment=0:1abjg8uc]HighPh.JPG[/attachment:1abjg8uc]

Now, I am aware that pH can fluctuate from morning to evening, and I did notice a much higher pH (in the purplish color) when I did an evening test a few days ago.

(I should also add that I checked the pH of the tap water being added, and it's pretty close to neutral, so I'm not raising the pH with my water changes).

From my understanding (and correct me if I'm wrong), but the nitrification process will naturally LOWER pH, but the PLANTS THEMSELVES will raise the pH. This is because the plants take out the carbon dioxide from the water making it more alkaline, thus raising the pH.

So my question is.....now that I've lost so many fish (but still have a TON of plants), should I get rid of some of the plants in order to not cause any drastic fluctuations in pH from morning-to-evening? Is that even a viable option? Or would plants have nothing to do with it?

As you can see from the above reading, my pH is probably between 7.6 - 8.0 in the morning, but it's probably only 8.4 during the night. Not sure if that's the cause or not. I am really baffled by all of these fish dying when my water seems to be fine.....doing frequent water changes with treated water, and not in high enough volume to shock the fish.

[David - WI]

I don't know, I'm far from being an expert, but it seems like you are walking a pretty fine line.

At 8.4 pH with your water at 75 degrees... even 0.2 ppm of ammonia puts you well into the "may be tolerated, but will cause long term harm" range; and if the ammonia even gets close to 0.5 ppm (say just prior to your water changes) you're in the "may be tolerated for a few days, harmful" range.

http://www.cnykoi.com/calculators/calcnh3c.asp

I'm thinking you were doing ok until the water warmed up and the fish got bigger this summer... and then the combination of temperature and ammonia levels caught up to you. Heating the water may have contributed to this last fatality?

[Jeff]

David - Perhaps. I think I will turn off the heater and let the water sit at natural temps. Any thoughts on my other question about treating the ENTIRE TANK with some kind of global application of Maracide or Coppersafe (both which are for parasitic treatments, in case the fish have anything)?

[Roger L.]

Jeff, I am no expert by any stretch of the imagination but I have been following your thread since it started. It seems to me that there my be to much adjustments being made and no solid progress. If it were my system I think I would back off of all adjustments and let Mother Nature take her course. Nothing has worked and all of the manipulation a may be shocking already stressed fish. Just a newbie observation.